Roadster pickup update

[Charlie Chops 1940]

I did get a chance to put a few miles on it this weekend. Sunday afternoon I noticed the oil pressure going away. Oil seemed a bit thinnish, maybe a little fuel diluted., so I changed the oil and filter and all seemed well. Drove it to a little local show yesterday where it got its first trophy. That was cool.

One of the things I wanted to do today was take the filter to my drag racer pal Steve and have him cut the top off it so we could examine the element. I did and found a lot of silver that looked like bearing insert flakes in the element pleats. He didn't think the oil was diluted to any high degree.

Tonight I dropped the pan and to my surprise I didn't find any evidence of insert failure - no appreciable wear, no flaking and no tracking on the rod or main journals. I'm a little mystified, but I'm in for the whole job so I'll pull the engine for complete disassembly and examination. Probably after Kzoo.

I suspect it could be cam bearings but I've never lost a set before. I'm using an aluminum cam gear so I suppose there might be some unusual wear there but that's not what the flakes looked like. There is a little end play in the crank though I haven't measured it and there didn't appear to be any wear on the rear inserts thrust area. I'll check it with an indicator when I've got it on a stand.

It was fun to get it out finally. My first impressions are that the motor is strong and the 3.73 gears seem about right. Very nimble, light steering and good brakes. The T50 5-speed seemed a bit balky on downshifts. Anyone know if those trannys used ATF instead of 90 wt gearlube? I can't find anything that says ATF - just seems I've heard it mentioned before.

Bummer.

Charlie

[kb426]

I can't remember dates for changes on a t5 but I'm sure none are supposed to use 90 wt. My son's 83 Mustang used a 50 wt. Those flakes you're seeing might be the pistons scuffing in. I'm with you though, I'd take it apart just so I could drive it with confidence.

[Fat Cat]

The T50 5-speed seemed a bit balky on downshifts. Anyone know if those trannys used ATF instead of 90 wt gearlube? I can't find anything that says ATF - just seems I've heard it mentioned before.

Charlie

according to this site it should have 80W-90. I know that some of the S-10 and ranger stuff used ATF but I don't have anymore helpful info for you.

[Charlie Chops 1940]

Frank - this is a BW T50...don't think it's the same as the Toyota. The BW was used in Vega/Monza applications. Thanks for the info though.

KB426 - possible on the pistons - I'll keep that in mind too. As you say better to examine it with the doubts I have now. Been "on the trailer" before for a major thrash, but in this case there isn't any compelling reason to work overtime.

Just disappointed, but maybe I'll learn something in the process.

[Bruce Dorsi]

<snip>Oil seemed a bit thinnish, maybe a little fuel diluted., so I changed the oil and filter and all seemed well.

One of the things I wanted to do today was take the filter to my drag racer pal Steve and have him cut the top off it so we could examine the element. I did and found a lot of silver that looked like bearing insert flakes in the element pleats. He didn't think the oil was diluted to any high degree.

****************
I don't know if you've seen the info in the link below.  ....This is one source advising of cam/lifter failures recently.  

I've seen this info from other sources as well, but of course this may not be the root of your problem.

If your oil was slightly diluted, it could have possibly aggravated a "weak spot."

You may want to inspect the lobes & lifters during your teardown.

It's a lengthy article, but the pertinent info is near the end:

http://www.hughesengines.com/general/techArticleDetail.asp?articleID=1000039

[tomslik]

we used to put a pint of atf in the trans to make 'em shift cold (on toyotas), never hurt anything...

[Charlie Chops 1940]

Thanks Bruce. Happens I ran the valves again yesterday and all appeared well. I have read that article and I spent a number of years in the camshaft business. The cam get a good check on wear, profile and ramp transitions before it goes back in.

Tom, I'll try the ATF thing in the tranny when it goes back in. Tranny works good otherwise.

Charlie

[Uncle Bob]

Just a commentary on the viscosity thing.  SAE 50 motor oil is in the same viscosity range as SAE 90 gear lube...............additive systems are VERY different though.  ATF is most like a 5w 20 by viscosity comparison.........again, different additive systems.

[Charlie Chops 1940]

Well, with everyones comments in mid I did a little more sluething tonight. I could not find any magnetic particals anywhere...cut filter element, oil pan, oil pump or in last nights drained oil. What I did find was a 3/4x1/4 inch very thin piece of metallic "foil" in the oil pan.

Suspicious, I started looking up into the block and found more of the same foil being extruded out around the middle cam journal.

I'm guessing that the cam bearing spun in the block and more than a little warm. That, at least explains the lost oil pressure. Strange.

It'll be interesting to see what the cam jounal looks like. Guess I'll start looking for a new cam kit.

Slocro - see if you can resize those two pics I sent you and add them here.




Charlie

S

[slocrow]

Wow, I don't think I ever saw a cam bearing spin but that sure explaines the oil pressure. I see you got the pics on, yourself.

Hummm, I wonder what a lot of duration sounds like on a 4 banger?

[purplepickup]

Well, it certainly pays to check things out when something doesn't seem right, doesn't it?  Maybe you caught the spun bearing before it damaged the cam.  Wonder what caused it tho.  I'm guessing you'll be checking alignment of the bores and cam straightness.  Maybe that cam bearing wasn't installed correctly and wasn't getting oil?

The good thing is that you caught it before other bad things happened.